smtpd Module¶
⚠️ REMOVED IN PYTHON 3.12: The smtpd module was deprecated and removed in Python 3.12. Use aiosmtpd or another asyncio-based server.
The smtpd module implements an SMTP server (daemon), allowing you to receive and process email.
Complexity Reference¶
| Operation | Time | Space | Notes |
|---|---|---|---|
| Server startup | O(1) | O(1) | Listen on port |
| Handle message | O(n) | O(n) | n = message size |
| Run loop | O(m) | O(m) | m = concurrent connections |
Creating SMTP Server¶
Simple SMTP Listener¶
# Legacy example (Python <= 3.11)
import smtpd
import asyncore
class MyServer(smtpd.SMTPServer):
def process_message(self, peer, mailfrom, rcpttos, data):
"""Process received message - O(n)"""
print(f"From: {mailfrom}")
print(f"To: {rcpttos}")
print(f"Message:\\n{data.decode()}")
return # Accept message
# Create server - O(1)
server = MyServer(('localhost', 25), None)
# Run event loop - O(m)
asyncore.loop()